Alphanecrovirus

VIRION

GENOME

Linear, ssRNA(+) genome of about 4 kb, which lacks a cap structure and a poly(A)tail.

GENE EXPRESSION

The virion RNA is infectious and serves as both the genome and viral messenger RNA. Two 5'-proximal ORFs are directly translated to produce the viral constituents of the replicase complex. RdRp is translated through suppression of termination at the end of ORF1. The downstream genes encoding the movement and capsid proteins are translated from subgenomic RNAs. ORF2 and ORF3 are necessary for cell-to-cell movement, while the capsid protein p29 is needed for particle assembly and systemic movement. Cap-independent translation is mediated possibly through the interaction between a 3'-cap-independent translation element and a 5’UTR stem-loop.

REPLICATION

CYTOPLASMIC

Virus penetrates into the host cell.

Uncoating, and release of the viral genomic RNA into the cytoplasm.

The viral RNA is translated to produce the two proteins necessary for RNA synthesis (replication and transcription).